Imaging thyroid cancer

Abstract

There are four main types of thyroid cancer: papillary, follicular, medullary and anaplastic types. Papillary and follicular cancers are well-differentiated cancers that originate from the thyroid follicle. They are the more common types of thyroid cancer, accounting for 80% and 10% of cases, respectively.1 Most clinically and ultrasound-detected thyroid nodules are benign, many representing purely cystic lesions known as colloid cysts. Solid or partly solid nodules however, should be further investigated since approximately one in four will be malignant. Although differentiated thyroid cancers are generally slow growing, lymph node metastases are present in 30-80% of cases at the time of first diagnosis.2 The outcome of treatment is good with a 98% 5-year survival,3 but these results depend on proper surgical treatment. The presence of lymph node metastases is the most common cause of thyroid cancer recurrence. Since most recurrences occur within the first five post-operative years, they may likely result from inadequate detection and resection at the time of initial management.4 Physical examination has shown poor accuracy in detection of lymph node metastases. Accurate staging of thyroid cancer depends on meticulous ultrasound evaluation and detailed reporting, which are crucial for accurate surgical planning.